Sony's PS Eye-based motion-tracking system that uses head movements as game controls, and which was recently shown at GDC, was merely a tech demo. This means it is unlikely to be coming to a shop near you soon.

A Sony representative told SPOnG this morning, "We have no details on the tracking software. As far as I'm aware it was developed by someone at SCEA and was shown at GDC as a technical demo of what is possible with the PS3 and PS Eye."